Feat/custom JSON encoder

[Flix6x]

Description

• Allow configuring a custom JSON encoder for job.get_meta() serialization in web.py.
• This can help users to implement a workaround in cases where job.meta contains objects that are not serializable by the default JSONEncoder.
• Fixes Allow configuring JSON encoder for job.get_meta() serialization in web.py #510.

Type of change

• New feature (non-breaking change which adds functionality)

Checklist:

• I have performed a self-review of my own code
• I have made corresponding changes to the documentation: please advise where this is necessary
• My changes generate no new warnings
• I have run tests (pytest) that prove my fix is effective or that my feature works
• I have updated the CHANGELOG.md file accordingly: this file seems to be missing?
• I have added tests that prove my fix is effective or that my feature works: the current test suite seem purposely light-weight; would you actually require a test for this feature?

[cjlapao]

@Flix6x Thanks for the work, if nothing will come up we will be releasing this on the end of this week

[Flix6x]

Hi @cjlapao no release yet I see? I was hoping to upgrade with this feature this week.

[cjlapao]

@Flix6x done, just released version 0.8.7